In the medical field, an X-ray imaging device refers to a device that allows a predetermined amount of X-rays penetrates a body part to be radiographed, and provides an image by using electrical signals generated from an X-ray detector on which the penetrated X-rays are incident. The X-rays penetrated through the body part generate different electrical signals according to the X-ray attenuation ratio of a location of the body part, and thus an image is realized through the electrical signals and location information.
However, the energy of the X-rays incident on the X-ray detector is influenced not only by the attenuation ratio according to a penetration path but also by an incidence angle and a distance from the X-ray source to each location of the incidence surface of the X-ray detector. Accordingly, in order to obtain an accurate X-ray image, it is required the work of correction for X-ray energy differences due to the differences in distance and angle. Hereinbelow, reference will be made in greater detail to the difference with reference to the accompanying drawings.
FIG. 1a is a view illustrating that an X-ray image is obtained using a conventional flat detector. And FIG. 1b is a view illustrating differences in distance according to locations, on which X-rays are incident, in the conventional flat detector. In the conventional dental X-ray imaging device, generally, an X-ray source 10 is a cone-beam type that radially emits X-rays within a predetermined angle range, and an X-ray detector is a flat detector 20 that detects X-ray energy incident on a flat surface having a predetermined area. When X-rays are projected onto the flat detector 20, a distance to a center of the flat detector 20 is R1, and a distance to an edge of the flat detector is R2, thereby the X-rays traveling distances become different. Further, X-rays are incident on the center of the flat detector 20 at a right angle, and on the contrary, X-rays are incident on the edge of the flat detector at a tilted angle by a distance apart from the center. Due to the differences, the detected result is inaccurate, and thus to compensate for this, the work of correction for an incidence location on the flat detector is required.